SOME OBSERVATIONS OF POLAR-CAP ABSORPTION IN THE NORTHERN AND SOUTHERN HEMISPHERES

• Published in: Canadian Journal of Physics
• Main Authors: Jelly, Doris H., Collins, C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1962
• Subjects: General Physics and Astronomy; Arctic; Antarctic; Antarc*
• Online Access: http://dx.doi.org/10.1139/p62-075; http://www.nrcresearchpress.com/doi/pdf/10.1139/p62-075

The phenomenon known as polar-cap absorption (PCA) has been studied by several different radio techniques and some of the characteristics of the absorbing regions are now fairly well known. In the present study the deviations of minimum frequencies (Δƒ min ), recorded by ionosondes at high-latitude Arctic and Antarctic stations, have been used synoptically to investigate the simultaneous occurrence of the absorbing regions in the northern and southern hemispheres. Detailed examination of these ionosonde data has revealed the occurrence of periods of weak absorption which have the characteristics of the large PCA events. Several of the PCA features such as starting times and durations are discussed and the morphology of one of the weak events is considered in some detail.